Chapter 3: Sleep (Grivas)

The most accurate physiological measure for distinguishing between the different stages of NREM sleep is the pattern of brain wave activity. This is because different stages of NREM sleep are associated with distinct patterns of brain wave activity, which can be measured using electroencephalography (EEG). These brain wave patterns, such as the presence of slow wave activity in deep NREM sleep, can be used to differentiate between the various stages of NREM sleep.

During the initial stages of a typical night's sleep, we experience periods of REM (Rapid Eye Movement) sleep, which is characterized by vivid dreaming and rapid eye movements. However, the correct answer is NREM (Non-Rapid Eye Movement) sleep. NREM sleep is a sleep period that occurs before REM sleep and is divided into three stages: N1, N2, and N3. NREM sleep is characterized by slower brain waves, reduced muscle activity, and the absence of rapid eye movements. It is during NREM sleep that our body and brain undergo restorative processes, such as tissue repair and memory consolidation.

In stages 3 and 4 of the NREM sleep period, delta waves are more common. This indicates a deeper level of sleep compared to stages 1 and 2. Delta waves are associated with slow-wave sleep, which is characterized by a decrease in muscle tone, heart rate, blood pressure, and body temperature. It is harder to wake the sleeper during these stages as sleep is deeper.

Sleep diaries can be used to collect self-reports when studying sleep. Sleep diaries are a simple and effective method where individuals record their sleep patterns, including the time they go to bed, the time they wake up, and any disturbances or issues they experienced during the night. This self-reporting method allows researchers to gather subjective information directly from the individuals themselves, providing valuable insights into their sleep habits, patterns, and quality. Sleep diaries are a non-invasive and cost-effective tool commonly used in sleep research and clinical practice.

During each complete progressive sleep cycle, the duration of REM sleep increases. This is because REM sleep, also known as rapid eye movement sleep, is the stage of sleep where dreaming occurs and is associated with various cognitive functions. As the sleep cycle progresses, the amount of time spent in REM sleep gradually increases, reaching its peak in the final stages of the sleep cycle. This increase in REM sleep duration is important for memory consolidation, emotional regulation, and overall brain development in adolescents.

Sleep deprivation refers to the condition of not getting enough sleep. The statement that sleep deprivation affects one's ability to perform cognitive tasks is true. When a person is sleep-deprived, their cognitive functions such as attention, memory, decision-making, and problem-solving are impaired. Lack of sleep can lead to difficulties in concentration, slower reaction times, decreased alertness, and decreased overall cognitive performance. These effects can have a significant impact on daily activities and tasks that require mental processing and focus.

During REM sleep, the body experiences muscle atonia, which is a state of muscle paralysis. This means that muscle tone actually decreases during REM sleep, rather than increasing. During this stage, the brain is highly active, and vivid dreaming often occurs. REM sleep typically occurs after a cycle of NREM sleep and tends to lengthen in duration as the night progresses.

Adolescence is a crucial period of growth and development, and adequate sleep is essential for overall health and well-being. Studies have shown that, on average, adolescents require around 9 hours of sleep per night. This is slightly more than the recommended 7-8 hours for adults, as the rapid physical and cognitive changes that occur during adolescence necessitate additional rest. Therefore, 9 hours of nightly sleep is the correct answer based on research findings.

The research design of this experiment is best described as repeated-measures because the same participants were tested under two different conditions (sleeping after learning and watching TV after learning). This design allows for a comparison within the same group of participants, which helps to control for individual differences and increases the internal validity of the study.

The correct answer is stage 4 sleep because the description of Elka's sleep patterns matches the characteristics of stage 4 sleep. Stage 4 sleep is characterized by the presence of low-frequency, high-amplitude delta waves in the EEG recording, which is mentioned in the question. Additionally, during stage 4 sleep, there is typically no eye movement, which is indicated by the absence of activity in the EOG recording. The fact that the researcher can hear Elka talking suggests that she is in a deep sleep state, further supporting the conclusion that she is in stage 4 sleep.

The effects of partial sleep deprivation impairing daily functioning can be attributed to accrued sleep debt. This refers to the cumulative lack of sleep over time, which can lead to cognitive and physical impairments. When individuals consistently do not get enough sleep, their bodies and brains are unable to fully recover and recharge, resulting in decreased alertness, concentration, memory, and overall performance. Accrued sleep debt can have long-term consequences on health and well-being, making it crucial to prioritize and maintain regular, sufficient sleep.

The experimenter used counterbalancing to control order effects. Counterbalancing is a technique used to minimize the impact of order effects, which occur when the order in which conditions or treatments are presented affects the participants' responses. By randomly assigning half of the participants to condition 1 first and the other half to condition 2 first, the experimenter ensures that any differences in performance between the two conditions are not solely due to the order in which they were presented.

During REM (Rapid Eye Movement) sleep, the brain is highly active and the majority of dreaming occurs. REM stage 1 is the initial phase of REM sleep, characterized by the onset of rapid eye movements and a mix of alpha and theta brain waves. Alpha waves are associated with relaxed wakefulness, while theta waves are linked to light sleep and drowsiness. Therefore, a mix of alpha and theta brain waves is most commonly observed during REM stage 1 sleep.

NREM stage 2 is the correct answer because during this stage of sleep, brain wave activity consists mainly of theta waves. Theta waves are slower in frequency than the alpha waves present during wakefulness and NREM stage 1. NREM stage 4 is characterized by the presence of delta waves, while REM sleep is associated with rapid eye movements and more active brain wave patterns.

When someone is sleep-deprived for a prolonged period of time, their cognitive abilities and attention span are significantly affected. As a result, they are more likely to make errors on tasks that require less mental effort and engagement, such as simple and boring tasks. This is because their reduced alertness and decreased ability to focus make it difficult for them to maintain accuracy and attention to detail on these types of tasks.